// Copyright 2022 jeff.li. and/or its affiliates.
// clang-format off
// Taken from https://github.com/veelion/python-farmhash/blob/master/src/farmhash.h
// with fixes applied:
// - add namespace ::tbir::runtime for fix conflict with origin version

// Copyright (c) 2014 Google, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// FarmHash, by Geoff Pike

//
// http://code.google.com/p/farmhash/
//
// This file provides a few functions for hashing strings and other
// data.  All of them are high-quality functions in the sense that
// they do well on standard tests such as Austin Appleby's SMHasher.
// They're also fast.  FarmHash is the successor to CityHash.
//
// Functions in the FarmHash family are not suitable for cryptography.
//
// WARNING: This code has been only lightly tested on big-endian platforms!
// It is known to work well on little-endian platforms that have a small penalty
// for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs.
// It should work on all 32-bit and 64-bit platforms that allow unaligned reads;
// bug reports are welcome.
//
// By the way, for some hash functions, given strings a and b, the hash
// of a+b is easily derived from the hashes of a and b.  This property
// doesn't hold for any hash functions in this file.

#pragma once

#include <cassert>
#include <cstdint>
#include <cstdlib>
#include <cstring>   // for memcpy and memset
#include <utility>

namespace tbir::runtime {

#if defined(FARMHASH_UINT128_T_DEFINED)
    inline uint64_t Uint128Low64(const uint128_t x) {
      return static_cast<uint64_t>(x);
    }
    inline uint64_t Uint128High64(const uint128_t x) {
      return static_cast<uint64_t>(x >> 64);
    }
    inline uint128_t Uint128(uint64_t lo, uint64_t hi) {
      return lo + (((uint128_t)hi) << 64);
    }
#else
    typedef std::pair<uint64_t, uint64_t> uint128_t;

    inline uint64_t Uint128Low64(const uint128_t x) { return x.first; }

    inline uint64_t Uint128High64(const uint128_t x) { return x.second; }

    inline uint128_t Uint128(uint64_t lo, uint64_t hi) { return uint128_t(lo, hi); }

#endif


    // BASIC STRING HASHING

    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    size_t Hash(const char *s, size_t len);

    // Hash function for a byte array.  Most useful in 32-bit binaries.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint32_t Hash32(const char *s, size_t len);

    // Hash function for a byte array.  For convenience, a 32-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint32_t Hash32WithSeed(const char *s, size_t len, uint32_t seed);

    // Hash 128 input bits down to 64 bits of output.
    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint64_t Hash64(const char *s, size_t len);

    // Hash function for a byte array.  For convenience, a 64-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint64_t Hash64WithSeed(const char *s, size_t len, uint64_t seed);

    // Hash function for a byte array.  For convenience, two seeds are also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint64_t Hash64WithSeeds(const char *s, size_t len,
                             uint64_t seed0, uint64_t seed1);

    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint128_t Hash128(const char *s, size_t len);

    // Hash function for a byte array.  For convenience, a 128-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    uint128_t Hash128WithSeed(const char *s, size_t len, uint128_t seed);

    // BASIC NON-STRING HASHING

    // This is intended to be a reasonably good hash function.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    inline uint64_t Hash128to64(uint128_t x) {
        // Murmur-inspired hashing.
        const uint64_t kMul = 0x9ddfea08eb382d69ULL;
        uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
        a ^= (a >> 47);
        uint64_t b = (Uint128High64(x) ^ a) * kMul;
        b ^= (b >> 47);
        b *= kMul;
        return b;
    }

    // FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)

    // Fingerprint function for a byte array.  Most useful in 32-bit binaries.
    uint32_t Fingerprint32(const char *s, size_t len);

    // Fingerprint function for a byte array.
    uint64_t Fingerprint64(const char *s, size_t len);

    // Fingerprint function for a byte array.
    uint128_t Fingerprint128(const char *s, size_t len);

    // This is intended to be a good fingerprinting primitive.
    // See below for more overloads.
    inline uint64_t Fingerprint(uint128_t x) {
        // Murmur-inspired hashing.
        const uint64_t kMul = 0x9ddfea08eb382d69ULL;
        uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
        a ^= (a >> 47);
        uint64_t b = (Uint128High64(x) ^ a) * kMul;
        b ^= (b >> 44);
        b *= kMul;
        b ^= (b >> 41);
        b *= kMul;
        return b;
    }

    // This is intended to be a good fingerprinting primitive.
    inline uint64_t Fingerprint(uint64_t x) {
        // Murmur-inspired hashing.
        const uint64_t kMul = 0x9ddfea08eb382d69ULL;
        uint64_t b = x * kMul;
        b ^= (b >> 44);
        b *= kMul;
        b ^= (b >> 41);
        b *= kMul;
        return b;
    }

#ifndef FARMHASH_NO_CXX_STRING

    // Convenience functions to hash or fingerprint C++ strings.
    // These require that Str::data() return a pointer to the first char
    // (as a const char*) and that Str::length() return the string's length;
    // they work with std::string, for example.

    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline size_t Hash(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Hash(s.data(), s.length());
    }

    // Hash function for a byte array.  Most useful in 32-bit binaries.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint32_t Hash32(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Hash32(s.data(), s.length());
    }

    // Hash function for a byte array.  For convenience, a 32-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint32_t Hash32WithSeed(const Str &s, uint32_t seed) {
        assert(sizeof(s[0]) == 1);
        return Hash32WithSeed(s.data(), s.length(), seed);
    }

    // Hash 128 input bits down to 64 bits of output.
    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint64_t Hash64(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Hash64(s.data(), s.length());
    }

    // Hash function for a byte array.  For convenience, a 64-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint64_t Hash64WithSeed(const Str &s, uint64_t seed) {
        assert(sizeof(s[0]) == 1);
        return Hash64WithSeed(s.data(), s.length(), seed);
    }

    // Hash function for a byte array.  For convenience, two seeds are also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint64_t Hash64WithSeeds(const Str &s, uint64_t seed0, uint64_t seed1) {
        assert(sizeof(s[0]) == 1);
        return Hash64WithSeeds(s.data(), s.length(), seed0, seed1);
    }

    // Hash function for a byte array.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint128_t Hash128(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Hash128(s.data(), s.length());
    }

    // Hash function for a byte array.  For convenience, a 128-bit seed is also
    // hashed into the result.
    // May change from time to time, may differ on different platforms, may differ
    // depending on NDEBUG.
    template<typename Str>
    inline uint128_t Hash128WithSeed(const Str &s, uint128_t seed) {
        assert(sizeof(s[0]) == 1);
        return Hash128(s.data(), s.length(), seed);
    }

    // FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)

    // Fingerprint function for a byte array.  Most useful in 32-bit binaries.
    template<typename Str>
    inline uint32_t Fingerprint32(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Fingerprint32(s.data(), s.length());
    }

    // Fingerprint 128 input bits down to 64 bits of output.
    // Fingerprint function for a byte array.
    template<typename Str>
    inline uint64_t Fingerprint64(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Fingerprint64(s.data(), s.length());
    }

    // Fingerprint function for a byte array.
    template<typename Str>
    inline uint128_t Fingerprint128(const Str &s) {
        assert(sizeof(s[0]) == 1);
        return Fingerprint128(s.data(), s.length());
    }

#endif

}  // namespace tbir::runtime

// clang-format on
